Production of chlqrobenzoyt benzoic acid



UNITED STATES PATENT OFFICE.

101m 11. wmss, or new roux, N. Y., AND enonen o. nun-s r, or wooncmrr-oir- HUDSON, AND RALPH S. POTTER, 0F GBAN'IWOOD, NEW JERSEY, ASSIGIBTORS- TO THE BARRETT COMPANY, A CORPORATION 0E NEW JERSEY.

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Toallwhamit concern:

Be it known at we, Jomr M. WEISS,

Gnome C. BAILEY, and RALPH S. Pom-rm, citizens of the United States, residi at (1) New York city, (2) Woodclifi-om udson, and (3 Grentwood .in the counties of (-1) New ork, (2) l'zludson, and (3 .Ber-

11, and States of (1) New York, 2) and g) New Jersey, have invented certain new and useful Improvements in Production-of Chlorobcnzoyl Benzoic Acid, of which the following is a specification. 1 V

This invention relates to the production ph alic acid anhydrid and chlorobenzol by means of aluminum'chlorid. The objects of the invention areto increase the yiel to increase the rapidity of production an to economize in the use of materials.

The invention relates more purficularly to improvements in the production of betas chloroanthre-quincne from Ehthelic acid anhydrid and chlorobenzol w ich has been described in German Patent No-76,288. In patent, it is directed that aluminum of 100 arts of phthalic unhydrid in 1000 parts of clflorohenzol in small portions until the evolution of hydrochloric acid ceases. No information as to the pre I'- able temperature is iven in this patent. We have found that i the directions of the atent are followed, there will be some pro-. notion of the chlorobenzoyl benzoic acid, but that the temperature at which theintroduction of the aluminum chlorid is carried out is very important. We have also found that aluminum chlorid may be introduced into a. hot mixture of phthalic anhydrid and chlorobenzol in a reatly excessive amount with but little ution in the evolution of hydrochloric acid ges with each successive portion of aluminum chlorid added. -We have found that aluminum chlorid when added to hot chlorobenzol alone gives ofl an amount of hydrochloric acid gas closely approximating one molecule of this gas for each molecule of aluminum chlorid used. Ifthe directions of the German patent are followed, hydrochloric acid gas will be given ofiuntll about a molecule of aluminum chlorid is added per molecule up chlorobenzoyl o benzoic acid from Y Specification otLottcriPatent. Patented Oct; 5, 1920. Application filed Deocmber 19,"19l9. Serial m. elem.

" of chlorohenhol present. We have found thet good yields of the chlorobcnzoyhbem' zorc acid may he. obtained with amuch less uantity of aluminum chlorid. It'hes also een found that increased 'elds may be obtained by an introduction 0 a mixture of phthe'hc anhydrid and aluminum chlorid mto the hot chlorobenzol over those obtained bg the introduction of the ulumm" um c lorid into the hot mixture of the chlorobenzol end. the phthalic anhydrid as directed inthe patent. In, addition, we have fo nd the which the most suitable temperatures: at reaction should he carried out in order to obtain the highest yields. We

have found these temperatures to be from 110 C. toxjust below the boiling point of the mixture. This boiling oint varies, accordm to the amount of soli from 30 to184= G.

ds introduced, We have found a l convenient range to be 118 to 123 C.

Noticeebly lower yields are obtained if these limits are exceeded, especially if the mixture be boiled. l 1

.We have also found that the quality of the aluminum chlorid For example, when the ordinary, pure sublimed aluminum chlorid of commerce is used, yields of the chlorob'enzoyl benzoic acid epproximatin 350% of time based on one molecule 0- phthelic anhy rid and 2 molecules of aluminum chlorid (A101,) charged are obtained, -When the fineparticles, small euou h to'pass through a. '20- mesh screen, are 'slfted out and the coarser pieces of the chlorid ere used, yields of twenty to twenty-five per cent. higher are obtained. Use of the line particles, the siftings, gives yields20 to 30% lower than is very important.

where the coerseand'the fine are used together. However, {if the coarse 15 ground to suflicient fineness to pass through a .QO-meshscreen or even finer, it will still give yields as large as the original coarse aluminum chlorid. It seems probable, therefore, that the siitings from the commercial roduct. are less pure than the large arti es, and in order; for the some to converted vention, the siftin-gs must e re-sublimed. Although not desiring to commit ourselves 7 into aluminumchloricl suitable for the pu oses of this into an definite theory for the e lanation of this phenomenon, we su gest t 1: poor yields may be due to by 'olysis of the aluminum chlorid.

Phthalic acid anhydrid is usually obtained in the form of large needles. We have found that the acid in this form is less suitable for this process than it is when finely ound. the ph alic acid anhydrid preferably to such fineness that it will pass throu h an SO-mesh screen and thereby obtain hi er'yields of the chlorobenzoyl benzoic aei than can be obtained with the ordinary largo crystals.

We have made another improvement over the German patent in the step of reci itating the chlorobenzoyl benzoic aci the German patent, it is directed that after the reaction mass into water and then decom osecl by iling with sodium carbonate. he alumina is then filtered ofi and the chlorobenzoyl benzoic acid precipitated from the filtrate by means of mineralncids. By this present invention, we have greatly cheapened and shortened this step of the recess. We accomplish this result by adc mg water to the reaction mass after it has cooled, and then adding approximatel one molecule of sulfuric acid per molecl e of phthalic anhydrid originally charged. The excess chlorobenzol may then be removed by steam distillation. e chlorobenzoyl benzoic acid is obtained directly as a precipitate upon adding the sulfuric acid as above mentioned an may be filtered and washed by the usual means. Aluminum sulfate may be obtained by evaporating the filtrate from the chlorobenzoy benzoic acid after the addition of sufiicient sulfuric acid to convert all the aluminum to the sulfate. This procedure not only saves the cost of the sodium carbon etc, but also saves the troublesome filtration of the alumina.

The chlorobenzoyl benzoic acid may be used "for any of the purposes for which 'it is adapted in the arts, but is especially valuable as an intermediate product for the production of alizarin. In roducing alizarin, the acid is condensed to ciloro-anthra-quinone, for example, by treating with concentrated sulfuric acid, and is then converted into alizarin in any convenient way, as by treating it with caustic alkali in the presence of an oxidizing agent.

Having described the general procedure a specific example is given below. It is to be understood that the proportions of materials and the temperatures may be varied somewhat from those given in the example without departing from the spirit and scope of the invention. The parts are by wei ht.

100 parts of finely ground phtha 'c anhydrid are mixed with 180 parts of coarse freshly sublimed aluminum chlorid. This We accordingly oomminutehas cooled thatit be 30111156.

mixture is gradually added with agitation to 1000 parts of chlorobenzol held at a temperature of 1Q0 C. The hydrochloric acid gas given off may be recovered. After the phthalic acid anh drid and aluminum chlorid mixture has been introduced, the temperature is kept at about 120 C. for a short time. After cooling, water or ice is added to the mixture and then 80 to 90 arts of 60 a H SO, added. The excess 0 oroben- Z0 is then removed by steam distillation. The crude chlorobenzoyl benzoic acid is filtered from the cooled mass. The addition of the proper amount of sulfuric acid and the concentration of thefiltrate will give aproximatcly 280 arts of aluminum sulfate.

he crude chloro nzoyl benzoic acid is then dried and washed.

If any phthalic acidanhydrid is present from the first reaction, as phthalic acid, it may be recovered either by filtering the hot reaction mixture after the chlorobenzol was I removed b steam distillation, in which case the phtha ic acid will so arate from the cooled filtrate and the ch orobenzoyl benzoic acid will remain as the undissolved residue, or the mixture from the steam distilletion may be cooled and then filtered, in which case the phthalic acid may be extracted from the crude chlorobenzoyl benzoic acid by extraction with hot water.

Claims:

1. In the process of produci chlorobenzoyl benzoic' acid, the step whic comprises treating phthalic acid anhydridwith chlorobenzol 1n the resenoe of commercial aluminum chlorid mm which suhstantiall all of the particles small enough to pass through a 20-mesh screen have been removed.

2. In the process of producin chlorobenzoyl benzoic acid, the size whic comprises introduciu a mixture 0 h'thalic acid anhydrid an aluminum orid into chlorobenzol maintained at a temperature above 110 C.

3. Inthe process of producing aoyl benzoic acid, the ste s which com arise mtroducin a mixture 0 hthalic aci anhydrid en alumimun ch orid intochlorobenzol, while maintaining the temperature between 110 C and the boilingkpoint of the solution while the reaction is to n lace 4. In the process of producing cil hrobenzoyl benzoic ac1d, the stc s which com rise chlorobenintroduci a miicture o phthalic aci anhydrid an aluminum chlorid into chlorounrcavtml phtl lic' flnllytll'ld, and drying the chlombenzoyl benzoic acid.

6, In the process of producing clilorolienzoyl bcnzoio acid, the steps which comprise introducing a mixture of phtllalic acid anhydrul and aluminum chlor'nl into (lllOlO- bonzul maintained at a temperature between 110" l. and the lmilin' point ul' said mixturv. in substantially tlupropmtiuns of 100 parks of phtlialic :\T\ll}\llltl and 180 part uf in aluminum ('l1l()ll(l to 1000 parts Hf vliloro benznl.

In testimony whereof we atllx mn' signat-mcs.

JOHN M. \YFIHS, 

